1. Field of the Invention
The present invention relates to a sealing arrangement for differential pressure piston-combustion chamber systems, which serve for the generation of propellant gases for barreled firearms from liquid, in particular hypergolic propellant components (hypergolic diergoles), and which are constructed with a differential pressure piston or ram located in the weapon housing, which is axially movable in coaxial relationship with the weapon barrel, and which includes a support piston projecting into the hollow shaft of the differential pressure piston, as well as propellant infeed and propellant discharge passageways.
Concepts are well known with regard to barreled firearms and, especially, automatic cannons with the generation of propellant gases from hypergolic liquid propellants. Such concepts are contemplated for a median firing cadence of about 800 shots/minute and for calibers of between 20 mm and 40 mm. Through investigations there could be ascertained that the firearms which are equipped for operation through hypergolic diergoles afford at least the same power output as do firearms of the usual type with propellant charge powders. Theoretical power output computations have indicated that at the same maximum gas pressures and the same weapon barrel length, in firearms with hypergolic liquid propellants there can be achieved higher muzzle velocities for the projectiles, wherein there must be further positively taken into consideration, that the heating up and the erosion of the weapon barrel are lower than those for barreled weapons employing propellant charge powders.
The hypergolic liquid propellant is a two-component propellant which consists of a fuel and an oxidizer. The fuel ignites hypergolically with the oxidizer, meaning, without the use of external energy, and possesses detonating time delays of less than five milliseconds after the commenced admixing and contacting, which provide interesting combinations for barreled weapons. Such propellant combinations are known from the rocket technology. Preferably employed as an oxidizer are white or red-smoking nitric acid or dinitrous tetroxide. By means of such an oxidizer, different fuels are mixed with varying degrees of hypergolicity and toxicity. The essential advantages of firearms or automatic or machine cannons with hypergolic liquid propellants in comparison with those employing propellant charge powders, are the lack of a cartridge for the receipt of the propellant charge, the lack of a detonating device, and the liquid aggregate condition of the propellant. Inasmuch as each component is stored and transported separately from the others, and each individual component per se is not explosive, there is extensively reduced the danger of any injury to the weapon carrier.
2. Discussion of the Prior Art
Numerous patent publications are known which illustrate firearms with a hypergolic diergole.
In the firearm pursuant to German Patent 17 28 074, the propellant injection is effectuated by means of a regeneratively driven differential pressure piston or ram. The injection nozzles include spring-loaded nonreturn valves. The start of the injection and the detonation is undertaken by an auxiliary injection arrangement, whose actuation is effected shortly prior to the forward impact of the differential pressure piston.
In the firearm pursuant to German Patent 17 28 077, the propellant injection is also effected through a regeneratively driven differential pressure piston, while the injection nozzles are equipped with a plate-and-slide valve which is arranged ahead thereof and which is remotely-controlled. The propellant aspiration is effected through the remotely-actuated forward motion of the differential pressure piston, and the start of the injection as well as the detonation are effected through the remotely-actuated return movement of the differential pressure piston.
The firearm pursuant to U.S. Pat. No. 2,981,153 possesses a propellant injection system formed by a plurality of regeneratively-operated differential pressure pistons which are not synchronized and which necessitate a precise correlation of the nozzles. The radial arrangement of the differential pressure pistons facilitates the provision of a small combustion chamber volume and a short coaxial projectile infeed. The injection nozzles are provided with needle valves which are pneumatically actuated.
German Patent 24 27 139 discloses a differential pressure piston-combustion chamber system for the generation of propellant gases from hypergolic fuel components for firearms which incorporates a guide cylinder for the differential pressure piston and injection pumps which are driven by the latter.
In all of the above-mentioned firearms pursuant to the current state of the technology, there are employed differential-pressure pistons or rams which are arranged so as to be axially movable, and are as a consequence subject to sealing problems at their head ends as well as at their shaft ends. By means of the gas pressure, the individual propellant components are pressed back, and enter the minute spaces between the components which are longitudinally movable relative to each other.